Modular seating arrangements or sectional sofas combining plain chair-type units, beds, curves, and recliner units to form a sofa-like arrangement have become increasingly popular. Because of differences in construction of a chair unit and a recliner unit and the mixing of various modules, in combination with the substantial weight of the completed sectional sofa unit, the joinder of separate modules into a single unit has been a problem heretofore not effectively solved.
A reclining mechanism is often spring loaded and includes footrest raising, seat sliding, back support pivoting, and head rest elevation, and has various anchor points, pivots and spring fastening locations on a frame. Accordingly, recliners typically include a metal frame. Similarly, chair beds use a retracting bed spring mechanism and folding mattress, also having linkage and pivots and a metal frame.
The forces [imposed] caused by movement of the entire assembly combine over the life of the sectional sofa and impose either great strains on components such as a wooden frame of an adjacent module, or cause misalignment of the reclining mechanism itself when adjacent modules resist flexing of the typically steel framework of the reclining mechanism.
Typical prior art solutions include use of complex, high-strength connectors to [impose] make a rigid connection between all elements. This has disadvantages in complexity and the added strength requirements for the component parts, or need for providing a high-strength frame, such as a steel frame, for all components. Additionally there are also potential disadvantages in difficulty of disassembly, added cost, and added weight. The loads imposed by lifting the end of a sectional sofa unit cause flexing, thereby misaligning the reclining mechanism, or causing other difficulties.